A Little Problem
by unlimitedricepudding
Summary: When an explosive accident with the chameleon arch de-ages the Doctor into a toddler, a bewildered Donna finds herself stuck in a position she definitely didn't sign up for: babysitting the defiant, unruly, three-year-old Last of the Time Lords.


A Little Problem

When an explosive accident with the chameleon arch de-ages the Doctor into a toddler, a bewildered Donna finds herself stuck in a position she definitely didn't sign up for: babysitting the defiant, unruly, three-year-old Last of the Time Lords.

* * *

 **Chapter One**

In the beginning of the first chapter of every TARDIS's instruction manual, it is made boldly and explicitly clear just how volatile a device the chameleon arch is.

Even with unrivalled Gallifreyan engineering, the apparatus – meant only to be deployed in the most dire of circumstances – remains highly unstable. A single malfunction of the device under the right conditions can do untold damage. And therefore it is vehemently stressed in the manual that the head pilot of a TARDIS needs to put proper safeguards in place to prevent catastrophe.

Unfortunately, however, the instruction manual that belonged to the sole remaining TARDIS in the universe had been, in a fit of supreme immaturity, chucked into a supernova. The pilot of this particular vessel had never even heard of any of these safeguards or safety measures (and even if he had, it is safe to assume he wouldn't have been bothered to follow them anyway).

Thus, after its only usage, the chameleon arch installed in this last TARDIS had been absentmindedly shoved up into wiring, buried where no one could really see it, and more or less forgotten – out of sight and entirely out of mind. Its gravity clamps were not clamped. Its time seal was unsealed. And most atrociously of all, its seatbelt was unfastened.

When this gross negligence is taken into consideration, the events of Sunday afternoon seem rather less shocking than Donna Noble found them.

* * *

"Spanner."

Donna pointedly lifted her magazine higher, popping a crisp in her mouth and giving the pale, upturned hand at her knee a very dirty look.

The fingers on the hand snapped impatiently at her, as if they knew what she was doing. "Donna, the spanner," arrived the request once more, emphasised with a beckoning gesture.

She glared at the hand in lieu of its owner. "I'm not your assistant, you know. Would it kill you to get something for yourself now and again?"

"Just hand it here. You're closer than me."

Because the jump seat had been overtaken by springs and wires and other spare parts, she was instead seated on the only other surface in the room: the least dangerous-looking edge of the console. And consequently, right beside her sat a large metal toolbox containing the shiny spanner in question. She narrowed her eyes. "What's the magic word?"

"Oh, I dunno, Chiswick?"

Bristling, Donna snatched the spanner out the box. Long, blue pinstriped legs branched incongruously from the underbelly of the controls, trailing across the floor below her, and she lobbed the heavy tool at them, in the hopes that the impact would be incredibly painful.

But to her annoyance, the Doctor's outstretched hand swung in a blur of inhuman dexterity, neatly plucking the tool out the air before it could dent his shins.

"Thank you."

She didn't reply.

And such had been the frosty atmosphere in the TARDIS for a fortnight, ever since the unfortunate visit to Midnight.

Donna had always known that the Doctor was susceptible to dark, turbulent mood swings. But what she had experienced over the last two weeks was unprecedented. His perpetual exuberance had completely evaporated in the wake of his harrowing experience on that space bus, and been replaced by withdrawn, quiet irritability.

All he had done, for fourteen whole days, was lay under the console and 'repair' things. In complete and utter silence.

Needless to say, this was a deeply unnerving change. In the past, even whilst in one of his moods, his gob still always had a mind of its own. He was physically incapable of lasting thirty minutes without talking to himself, or blurting out an idea for a trip, or sharing a useless, obscure factoid.

Now the only time she heard him speak unprompted was when he asked her to fetch something out of that bloody toolbox.

Donna had tolerated this for the first week, knowing that he must have been working through the trauma from his experiences on Midnight. But come the second week her patience was gone. Traumatised or not, his behaviour was properly absurd. He didn't eat or sleep. She'd not even seen him get up to go to the loo once. He refused to talk about Midnight, even though she could plainly see how much the ordeal had affected him. When she tried to convince him to at the very least take better care of himself, the only response she received was a tired, sighed, "I'm fine, Donna."

She didn't know how to handle him when he was like this. Yelling – her usual recourse – had proven ineffective. And she was worried. She'd never once thought it possible that she would actually _miss_ the sound of his endless rambles, but as barmy as it was, she did. She missed him hovering far too closely at her shoulder and making withering remarks about her habit of reading rubbish tabloids – missed hearing him shout at his ship and grumble to her about fluid links as if she had the faintest clue what he was going on about – missed telling him to shut up when he waffled for hours about tree planets and ice planets and vegan planets and all other sorts of nonsense places.

He was an innately talkative bloke. The Doctor being quiet and morose was like Donna suddenly becoming even-tempered and mastering subtlety – it was an unsettling notion no matter how you looked at it. The man had the universe's most ridiculously expressive face. It was a face meant to lift into twinkling grins or scrunch in confusion or narrow into that disapproving teacher look he gave her sometimes. Seeing that wonderful face so tired and expressionless just felt _wrong._

Donna reasoned, however, that the Earth would be imperilled again at some point. Aliens seemed very insistent upon invading/harvesting/obliterating her home planet, after all. Once they made another attempt, then he'd have no choice but to emerge from under that console and make himself useful. She just needed to be patient. _Something_ , she thought, had to happen eventually to change his mindset.

What she did not know was that this _something_ would occur in a mere one-hundred and eighteen seconds.

Both occupants of the ship, completely unaware of what was going to happen in approximately two minutes, had re-engaged in their own respective activities. The Doctor murmured softly to himself about dust, sniffed a little, and lapsed into more silence. Rather annoyed that all he seemed to care about was the state of the bottom of the console – hardly even the most interesting side – Donna ignored him, flicking absently through her magazine as she tossed another crisp in her mouth and crunched on the snack.

It was at this crucial moment that, unbeknownst to her, small, microscopic particles spewed from the surface of the poor crisp, as soon as her teeth cracked into it. These particles hurtled down towards a remarkably delicate slot on the console at top speed, bearing the faintest hint of salt and grease and potato.

Nothing happened, obviously.

Then the Doctor's mutterings about dust finally came to fruition as he proceeded to drop his spanner and let out an enormous sneeze.

This jarringly loud _clang_ and _achoo_ combination, erupting as it did from right under her perch, made Donna jump in surprise. Her bag of crisps jumped with her, crinkling as her fist tightened on it. Nearly half the bag sloshed out onto her lap and onto the console: right down into that delicate slot.

The result was spectacular.

There was a red-hot spark. A bellow that put the sneeze to shame issued from under the console. The Doctor instantly attempted to retreat, moving so quickly he ended up whacking himself on the edge of the console and procuring a significant bruise above his right eyebrow. Donna didn't have time to react – a column of scalding smoke surged out the top of the console, singeing her shirt and her and sending her flying off the controls. A larger, even angrier collection of sparks followed.

Something that looked quite important exploded.

To Donna, the next few moments melded into a hazy montage of chaos. The room trembled and quaked and sparked all over, bulbs blowing on the console. A crack split its way down the Time Rotor with an almighty splintering sound. The Doctor swore frantically, and pushed past her to start yanking on levers, struggling to reign his ship in. Lights flashed in distressing hues of red. Three separate klaxons all began to scream at once.

And then, in all the frightening, frantic movement, the Doctor froze.

" _You've dribbled crisps in_ _the helmic regulator_!"

It was, Donna realised with immense satisfaction, the most emotive he'd been all week.

"Well, _sorry_ ," she offered, not feeling very sorry in the slightest, trying not to be pleased at the tight anger he was so clearly trying to keep off his face. "Didn't mean to. And it's _your_ fault I spilled them, anyway. Who in the world sneezes like that?"

"What have I told you," he shouted, voice rising above all three of the klaxons as he hurled the now-empty, incriminating plastic bag at the floor, "about eating in the console room?"

She was about to snap back that he'd once warned her not to eat ice cream in the console room – nothing at all had been said about crisps, so she was technically innocent, thank you very much – but before she could retort, the TARDIS bucked, throwing both its passengers to the floor.

A floor which, Donna couldn't help but notice, was beginning to tilt the wrong way.

"The gravitational circuits are failing!" The Doctor struggled to get back to the console. "Hold onto something!" he yelled over his shoulder.

This seemed like a reasonable course of action, so she hastily grabbed the nearby railing. The Time Lord across the room was a frenetic blur, hanging onto the console as he tried to control the time machine. The floor turned entirely sideways, and Donna yelped as her feet slipped off the grating, her knuckles turning white as her legs dangled. Directly in front of her was the mass of wires she never paid attention to – as it was usually in its rightful spot above her head. The alarm continued to blare, and metal stretched and screamed. She closed her eyes and clung onto the railing for dear life.

The room somersaulted.

It all seemed like somewhat of an overreaction to crisps, in Donna's opinion.

She lost her grip, screamed, and fell. But her landing was cushioned – fall broken by an unidentified cold and bony object.

"Ow!" the Doctor wheezed, the air knocked out of him by fallen companion. "Donna!"

"It's not my fault!" She scrambled up off him, falling on her side into the hard rubber blanket of wires. "What happened?"

"The gravity failed." He sounded rather upset about it as he sat up, and so Donna made the educated assumption that this was a bad thing. "Automatic shutdown. Without her own to keep her buoyant, the TARDIS was dragged to the nearest centre of gravity."

"Which is?"

"A planet, odds are."

"Which one?"

"Well, let me just have a look at the monitor." His eyes widened mockingly, and lifted to the ceiling where the console now resided. "Oh, _wait._ "

She glared. "Look, I said I was sorry. Are we stuck up here?" She paused. "I mean, _down_ here."

"Yeah, just a _bit_ , Donna. The door's several metres above your head, in case you hadn't noticed." He flopped back into the wires, catching his breath and throwing a frustrated hand over his eyes. "Crisps," he huffed. " _Crisps_. Tell them not to wander off. Tell them not to talk to strangers. Tell them not to eat in the console room – and what happens? I don't know _why_ I bother."

Donna was no longer paying attention to him, however. Her attention had been taken by something behind him. "Uh…Doctor?" she asked, tentative.

"Hmm?" he grunted. "You planning on wrecking my TARDIS again?"

"No, there's a…well, whatever that thing right there is. Is it _supposed_ to be fizzling like that?"

"What?" He peeked through his hand. "What's fizzling?" With a frown, he sat up straight and turned around.

His eyes landed on the helmet-like device lying a mere four feet away. Electricity popped and sizzled along its metal surface, surging from the long cord that trailed from the top of the device.

The Doctor stiffened.

Before Donna could get out the words to ask him what was wrong, one-hundred and seventy odd pounds of Time Lord bowled her over.

Her eyes flew wide in shock, and she instantly struggled, indignant. "Oi! Off!" She felt his knees clamp on either side of her hips, and his chest pressed into her back as he hunched over her. "Get off of me, Dumbo!"

The explosion was deafening.

* * *

Her ears rang for an impressive full minute.

It took even longer to regain her bearings. Her surroundings came into painful, blurry focus, discoloured spots of light lingering in her vision. With a groan, she got up to her knees. Smoke was thick and heavy in the air, and she coughed, flapping a hand. "Doctor?" she croaked.

The silence that responded felt tangible. With effort, she managed to stand, ankle-deep in wires. "What happened?" she wondered to herself, frowning in puzzlement.

Some terrible instinct niggled at her, and told her to look over her shoulder.

She did.

The burnt-out helmet device sat a few feet away, only a charred husk now. She scratched at her head, then took a step closer to the helmet to investigate. Her foot landed on something soft. Donna frowned and looked down.

Underneath her shoe were the Doctor's clothes, stacked up in a mound and decidedly void of their owner.

She struggled to keep her breathing steady as she stared at the evidence. Her brain repeatedly refused to accept the logical conclusion that her eyes were offering. Slowly, she sank down to her knees and touched the pinstriped jacket. It was still faintly warm.

It made no sense. He was gone, somehow; but they were stuck in the TARDIS. Which meant there was nowhere to go for him to go.

Donna found herself shaking her head, unable to even process the thought. _The Doctor is –_ she prodded at one flat lapel – _he can't be, he's not_ – she fished the sonic screwdriver from his pocket –

Something moved, very abruptly, in the shirt.

She recoiled in shock, and then gaped as the thing in the shirt moved again. It shifted upwards, then down. Then it came to another halt.

Donna swallowed hard – around the lump of suppressed emotion that had thankfully not been able to rise to the surface – and reached out a careful hand.

Swiftly, she flicked one flap of his jacket open. The thing in the shirt twisted once more, rotating around in an disoriented circle. She hesitated. And then, quickly, holding her breath, she pulled the first button of the shirt loose. The neck of the garment slouched downward.

A small head of ruffled hair poked out of the collar.

"Doctor…?" she whispered haltingly, stuck somewhere in the vague space between uneasiness and hope. The head, puzzled, swivelled in her direction.

Donna mustered every bit of courage she had, and unfastened two last buttons.

The shirt fell open at the top.

Staring cautiously up at her was a little boy no older than three: pale and small and freckled, with a distinct bruise above his right eyebrow.

"Oh my God," she breathed. "No _way_."

This sentiment was repeated several times, with increasing degrees of bewilderedness. She had seen plenty of bizarre things whilst travelling with the Doctor – giant spiders and volcano people and man-eating shadows – but this took the biscuit. The child in front of her brought up a chubby fist to rub at one of his eyes, expression wary as he peered up at her. He was entirely swallowed up by the button-up shirt that had once fit perfectly.

"You're…" _This_ particular logical conclusion wasn't as difficult to accept as her first assumption, but it was no less perturbing of a thought. "You're the Doctor, aren't you?"

There was no sign of recognition at the name. He merely stuck his thumb in his mouth and continued to watch her apprehensively.

"You're the Doctor," Donna repeated, slower, the realisation just beginning to sink in. She reached out to poke the kid's shoulder – just to make sure it was real and she wasn't concussed somewhere, stuck in a weird dreamland of her own mind's creation.

He was tangible, unfortunately. And as soon as her finger touched his shoulder, brown eyes went wide. He took one uncertain, tottering step backwards – then lost his balance and toppled onto his bum. He drew in a surprised gasp. The pout was instantaneous.

"It's me," she said. "Donna. Your…friend. Do you remember me?"

He said nothing, his face half-hidden in the shirt.

"Can you talk?"

Silence.

"Okay," she hedged awkwardly, "apparently not. Can you understand anything I'm saying?"

There was neither a negative nor affirmative; only the ongoing pout, which she could infer nothing from.

"Right, this is bad," she muttered, leaning back on her heels and raking a hand through her hair. "We're stuck, and now you can't remember me, and you're…like that. All...small. _How_ did that happen? No, actually, forget it. I probably don't want to know. But you have to change back, or we'll never get out."

His lip trembled.

"We'll be stuck down here for weeks. Months. No one will know to look." A horrible thought struck her. "If this planet's even got people on it. We could spend years down here. Wait – no. Oh, God, we'll starve to death first, won't we?"

This string of concerns would have perhaps gone over better had she not actually voiced it aloud. Almost at once, the big brown eyes filled with tears.

And at the exact same moment, rather unhelpfully, something began to pound on the TARDIS door.


End file.
